It is not much to look at in itself: less than half a metre tall, with a square socket cut into its top. But that socket is the point. It once held a cross, and the base that remains is a quiet marker of a devotional landscape that drew pilgrims for centuries.

The cross-base was recorded by the antiquarian R. A. S. Macalister in 1916 to 1917, who noted its dimensions with characteristic precision: the stone stands 0.48 metres high, with a socket 0.35 metres square and 0.12 metres deep. A cross-base is exactly what the name suggests, a shaped stone designed to anchor a free-standing cross, and the socket gives a sense of the scale of whatever once rose from it. Inis Cealtra, also anglicised as Holy Island, was an important early Christian monastic site associated with Saint Caimin, and the island retains a remarkable concentration of medieval remains, churches among them. The building beside which this base stands is called the Confessional, a name that reflects later folk usage rather than any proven liturgical function, and the east door beside which the base sits would have faced the rising sun, as was conventional in early Christian church orientation.